The present invention relates to a wave guide resonator device and a filter structure provided therewith.
The European Patent Document EP 438 807 B1 discloses a waveguide resonator device in which a plurality of supporting bars are provided for centrally fixing a dielectric in the waveguide. The supporting bars are mounted on the waveguide and introduced in the dielectric insert through corresponding openings on its outer periphery.
The European Patent Document EP 351 840 A2 discloses a resonator with the dielectric insert. The insert is held by two plates provided with special centering devices. The embracing of the insert by the centering device can cause thermal stresses.
The European Patent Document EP 104 735 B1 discloses a waveguide resonator with tuning screws facing in direction of the dielectric insert. The European Patent Document EP 328 948 B1 discloses a dielectric waveguide resonator in which the dielectric insert is centrally fixable in a chuck system adjustable by three screws in the waveguide. The U.S. Pat. No. 3,155,965 discloses a supporting structure for a ferrite body in a hollow guide with radial supporting pins mounted on the periphery of the ferrite body.
Accordingly, it is an object of the present invention to provide a waveguide resonator device, which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in a waveguide resonator device, which has a waveguide, a dielectric insert inside a waveguide, several clamping bodies for fixing the dielectric insert inside the waveguide, the clamping bodies being arranged between the waveguide and an outer periphery of the dielectric insert and contracting the dielectric insert only tangentially, at least one supporting element for the dielectric insert for fixing it in a direction deviating from the fixing direction of the dielectric insert by the clamping body.
When the waveguide resonator device is designed in accordance with the present invention, thermal stresses are better absorbed than in the known arrangements since no special mountings are needed. The device in accordance with the present invention is easy to manufacture. No openings must be provided in the dielectric insert as in the device disclosed in the European Patent Document EP 438 807 B1. An expensive chuck system disclosed in the European Patent Document EP 328 948 B1 also is not needed. Despite this, a very accurate fixing/holding of the dielectric insert in the wave propagation direction of the waveguide (hollow guide) is possible, due to the supporting element and also perpendicular to wave propagation direction in a transverse plane, without unfavorably affecting the thermal stresses. Since no changes must be performed in the dielectric insert (mountings, openings, etc.) no interference points are formed which can worsen the resonator quality. With the features of the present invention, any dielectric inserts can be selected, such as for example balls, cylinders, without changing the holding device. The dielectric inserts of different geometry can be exchanged, for example the cylinder can be exchanged with the ball and vice versa. Thereby the arrangement in accordance with the present invention can be used universally and suitable for different applications, for example different filter structures, multi-mode filters, etc. The supporting element has no centering means which can lead to unfavorable thermal stresses.
The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.